U.S. patent number 10,821,210 [Application Number 14/372,146] was granted by the patent office on 2020-11-03 for injections.
This patent grant is currently assigned to STABLEPHARMA LTD. The grantee listed for this patent is Stablepharma Limited. Invention is credited to Bruce Roser.
United States Patent |
10,821,210 |
Roser |
November 3, 2020 |
Injections
Abstract
A syringe containing a compressible porous matrix, which
compressible porous matrix has in it a pharmaceutical in a soluble
glass, Methods of producing and using the syringe, and compressible
porous matrix inserts for insertion into a syringe barrel are also
provided.
Inventors: |
Roser; Bruce (Cambridge,
GB) |
Applicant: |
Name |
City |
State |
Country |
Type |
Stablepharma Limited |
Somerset |
N/A |
GB |
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|
Assignee: |
STABLEPHARMA LTD (Bath,
GB)
|
Family
ID: |
1000005154750 |
Appl.
No.: |
14/372,146 |
Filed: |
January 28, 2013 |
PCT
Filed: |
January 28, 2013 |
PCT No.: |
PCT/GB2013/050183 |
371(c)(1),(2),(4) Date: |
July 14, 2014 |
PCT
Pub. No.: |
WO2013/110956 |
PCT
Pub. Date: |
August 01, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140350483 A1 |
Nov 27, 2014 |
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Foreign Application Priority Data
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|
|
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Jan 27, 2012 [GB] |
|
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1201426.2 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M
5/3129 (20130101); A61L 31/026 (20130101); A61K
9/122 (20130101); A61M 5/178 (20130101); A61L
31/146 (20130101); A61K 9/0019 (20130101); A61L
31/125 (20130101); A61L 31/16 (20130101); A61M
5/3145 (20130101); A61L 2300/438 (20130101) |
Current International
Class: |
A61L
31/16 (20060101); A61K 9/12 (20060101); A61L
31/02 (20060101); A61L 31/12 (20060101); A61M
5/178 (20060101); A61K 9/00 (20060101); A61L
31/14 (20060101); A61M 5/31 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1449523 |
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Aug 2004 |
|
EP |
|
1452171 |
|
Sep 2004 |
|
EP |
|
2187191 |
|
Sep 1987 |
|
GB |
|
2429646 |
|
Mar 2007 |
|
GB |
|
WO 87/00196 |
|
Jan 1987 |
|
WO |
|
WO 96/40077 |
|
Dec 1996 |
|
WO |
|
WO 99/27983 |
|
Jun 1999 |
|
WO |
|
WO 2007/057717 |
|
May 2007 |
|
WO |
|
WO 2011/042542 |
|
Apr 2011 |
|
WO |
|
WO 2011/098837 |
|
Aug 2011 |
|
WO |
|
Other References
International Search Report and Written Opinion dated May 16, 2013
for International application No. PCT/GB2013/050183. cited by
applicant .
United Kingdom Search Report dated May 9, 2012 for Great Britain
Application No. GB1201426.2. cited by applicant .
Green & Angell, 1989 J. Phys. Chem. 93:2880-2882, "Phase
relations and vitrification in saccharide water solutions and the
trehalose anamaly". cited by applicant .
Jones, et al., 1997 Journal of Controlled Release 49(1):71-79,
"Mucoadhesive, syringable drug delivery systems for controlled
application of metronidazole to the periodontal pocket: In vitro
release kinetics, syringeability, mechanical and mucoadhesive
properties". cited by applicant .
Sanchez, et al., 1989, Proc. Nat. Acad. Sci 86:481-485,
"Recombinant system for overexpression of cholera toxin B subunit
in Vibrio cholera as a basis for vaccine development". cited by
applicant .
Takashi, et al., 1990 Nature 344:873-875, "Induction of CD8
cytotoxic T cells by immunization with purified HIV-1 envelope
protein in ISCOMs". cited by applicant .
WHO, UNICEF, 2009, World Bank, "State of the world's vaccines and
immunization" 3.sup.rd ed., Geneva, World Health Organization.
cited by applicant .
Lloyd, et al., 1998, Genetic Engineering News, "Revolutionizing
Immunizations". cited by applicant .
Lloyd, 2000, World Health Organization, Geneva, in collaboration
with Department of Vaccines and Biological UNICEF, "Technologies
for vaccine delivery in the 21.sup.st Century". cited by applicant
.
Lloyd and Aguado, 1998, WHO Publication, "Pre-Filled monodose
Injection Devices: A safety standard for new vaccines, or a
revolution in the delivery of immunizations?". cited by applicant
.
Aguado, et al., WHO Publication No. A59781, vol. 12, No. 2, 1998,
"General Policy issues: injectable solid vaccines: a role in future
immunization?", 3 pgs. cited by applicant.
|
Primary Examiner: Mehta; Bhisma
Assistant Examiner: Darb; Hamza A
Attorney, Agent or Firm: Adsero IP
Claims
The invention claimed is:
1. A pharmaceutical syringe comprising a syringe barrel comprising
an interior syringe barrel wall, a proximal opening configured to
receive a plunger in contact with the interior syringe barrel wall,
and an integrally formed outlet connectable to a needle, the
syringe barrel containing a compressible porous matrix, wherein the
compressible porous matrix contains a pharmaceutical suitable for
administration into a human patient and wherein the pharmaceutical
is in a soluble glass in the compressible porous matrix.
2. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix in a non-compressed state occupies at
least about 10% of a volume of the syringe barrel.
3. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix has a compressibility of about 2:1 or
more.
4. The pharmaceutical syringe according to claim 1, wherein a gap
for a passage of air during venting of the syringe is present
between the compressible porous matrix and the interior syringe
barrel wall.
5. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix is in the form of an elongate block.
6. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix is in a form of a block having a
non-circular cross section.
7. The pharmaceutical syringe according to claim 6 wherein the
block has a rectangular cross section.
8. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix is a foam, a sponge, or a fibrous
body.
9. The pharmaceutical syringe according to claim 8, wherein the
compressible porous matrix is cellulose foam, polyurethane foam, or
melamine foam.
10. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix has a functional pore size of between:
a) 1 micron and 2 mm; b) 10 micron and 1 mm; or c) 10 micron and
100 micron.
11. The pharmaceutical syringe according claim 1, wherein the
compressible porous matrix is hydrophilic for an application of
water soluble glassy substances.
12. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix is hydrophobic for an application of oil
soluble glassy substances.
13. The pharmaceutical syringe according to claim 1, wherein the
pharmaceutical is stabilized in the soluble glass on the
compressible porous matrix.
14. The pharmaceutical syringe according to claim 1, wherein the
soluble glass is an amino acid glass, a sugar glass, a
hydrophobically modified sugar glass, a carbohydrate glass, or a
mixture thereof.
15. The pharmaceutical syringe according to claim 14 wherein the
soluable glass is a trehalose glass.
16. The pharmaceutical syringe according to claim 1, wherein the
compressible porous matrix is fixed to a seal of a syringe
plunger.
17. The pharmaceutical syringe according to claim 1 wherein the
outlet is directly connectable to the needle.
18. The pharmaceutical syringe according to claim 1 further
comprising the plunger slideably housed within the barrel, wherein
the compressible porous matrix is located between the plunger and
the outlet such that partial withdrawal of the plunger to aspirate
a carrier liquid into the barrel rehydrates the compressible porous
matrix such that the soluble glass containing the pharmaceutical
dissolves.
19. The pharmaceutical syringe according to claim 18 wherein
movement of the plunger to discharge the carrier liquid in the
barrel results in compression of the compressible porous
matrix.
20. The pharmaceutical syringe according to claim 19 wherein, when
the plunger is fully depressed towards the outlet, the compressible
porous matrix is compressed and the carrier liquid in the
compressible porous matrix is expelled therefrom and exits the
syringe via the outlet.
21. A method of producing a compressible porous matrix insert
comprising contacting a compressible porous matrix with a solution
of a glass-forming material, which solution contains a
pharmaceutical for delivery into a patient, and drying the solution
to form a glass in the compressible porous matrix, which glass
comprises the pharmaceutical, wherein the compressible porous
matrix is capable of being placed into a barrel of a pharmaceutical
syringe comprising a syringe barrel comprising an interior syringe
barrel wall, a proximal opening configured to receive a plunger in
contact with the interior syringe barrel wall, and an integrally
formed outlet at a distal end of the syringe barrel connectable to
a needle.
22. The method according to claim 21, comprising treating the
compressible porous matrix with a blocking agent before contacting
the compressible porous matrix with the solution of glass-forming
material containing the pharmaceutical.
23. The method according to claim 21 comprising treating the
compressible porous matrix with a surfactant.
Description
RELATED APPLICATIONS
This application is a 35 U.S.C. .sctn. 371 national phase
application of PCT/GB2013/050183 (WO 2013/110956) filed on Jan. 28,
2013, entitled "Improved Injections", which application claims the
benefit of Great Britain Application Serial No. 1201426.2, filed
Jan. 27, 2012, which is incorporated herein by reference in its
entirety.
INVENTION FIELD
The invention refers to methods for the parenteral injection of
medicines. In particular, a hypodermic syringe, typically used in
the administration of medicaments, in which drugs or vaccines are
stabilised in a porous matrix contained in the barrel of the
syringe.
BACKGROUND
The syringe has a long history. A type of syringe with a barrel and
plunger was in use in Roman times. However, pharmaceuticals have
only been routinely injected using the hypodermic needle and
syringe since their invention around 160 years ago. Surprisingly,
the appearance and basic design of the syringe has changed little
in more than a century and a half since then. A series of
refinements has led to the highly efficient standard disposable
syringe of today which still works in the same way as the original
device. Sixteen billion syringes are used annually. The enduring
popularity indicates an impressive "fitness for purpose". However
serious drawbacks do exist and are only tolerated because no
effective solution to them has yet been devised.
The first drawback is that the standard syringe as supplied must be
manually filled at the time of injection with a precisely aspirated
dose of the pharmaceutical. This is usually done from a separately
supplied vial containing the drug in solution. Apart from the cost
and inconvenience of supplying the vial, this process sometimes
leads to aspiration of an incorrect dose or even the incorrect
drugs being filled from the wrong vial and injected.
A syringe that was supplied pre-filled with the correct dose
already in it would be a cheaper and safer alternative. Several
attempts have been made to develop and popularise such pre-filled
syringes (WO96/40077, WO99/27983) but pre-filled syringes also
suffer from serious drawbacks. Firstly, although an empty syringe
can be stored indefinitely at room temperature, when pre-filled
with more labile drugs, they need refrigerated storage. Because the
standard plastic syringes are slightly permeable to water vapour
they cannot be used to store drugs dissolved in water except for a
short time. Otherwise the drug maybe damaged by over-concentration
and the correctness of the dose becomes uncertain. Alternatively,
glass syringes, which are impermeable to water vapour, can be used
but they add to the cost of injections and also constitute a sharps
hazard. Broken glass syringes may injure both the patient and the
health worker.
Secondly, although the necessity of refrigerating most unstable
drugs can be ameliorated by drying the drug (usually in conjunction
with stabilising agents) the results are less than perfect. Drugs
that are freeze-dried in ampoules are still refrigerated for
prolonged storage and still need to be aspirated into the syringe
after re-hydration. An alternative, drying drug solutions inside
the syringe itself, can be employed. For effective usability, the
dried drug must be in a finely divided form so as to dissolve
immediately on rehydration. This dried form can be achieved by
either freeze drying (WO99/27983) or vacuum foam drying
(WO96/40077). These are difficult and expensive processes. Drugs
freeze dried in this way are usually kept refrigerated for optimum
stability. However, carefully formulated and processed vacuum foam
drying can provide a room-temperature-storable, safe and convenient
product. However there is a large variability in the degree of foam
formation with many syringes failing to foam at all. The formidable
manufacturing difficulties of achieving successful drying within
the syringe containing the pharmaceutical in liquid form and the
high costs have stifled uptake of the process. A further technical
disadvantage is that dried products of this type still require
several minutes to redissolve completely and are not suitable as
immediately injectable formulations.
This problem is particularly acute in the vaccine industry since
virtually all vaccines are unstable to some degree and are required
to be held in refrigerated storage. This "cold chain", which must
extend all the way from the factory to provincial depots, is
unreliable and frequently breaks down. In 2008 $17 billion worth of
vaccines were administered worldwide. Between 2006 and 2015 the
cost of scaling up coverage and delivering new vaccines worldwide
is expected to rise to $76 billion (WHO, UNICEF, World Bank. Stale
of the world's vaccines and immunization, 3rd ed. Geneva, World
Health Organization, (2009)). The World Health Organization (WHO)
point out that this will not be possible using standard vaccine
formats ("Revolutionizing Immunizations." Jodar L., Aguado T, Lloyd
J and Lambert P-H. Genetic Engineering News Feb. 15 (1998)). The
cost of the cold chain for the vaccine industry and for
non-governmental health organizations running immunization
campaigns is enormous. The WHO has estimated that just the
maintenance cost of the cold chain is over $200 million annually.
In addition, immunization campaigns may reach only those
living-close to the last link of the cold chain. Because of
breakdowns in correct temperature storage between 50 and 70% of all
vaccines are damaged (PATH. Preventing Accidental Freezing in the
Cold Chain: An Introduction to Cold Chain Freezing and Some Options
for Reducing It (2003)). A most important requirement of any new
process for stabilising and delivering vaccines is determined by
the very large cost of world-wide vaccination efforts. The
expensive technologies described above are of no practical use in
most areas.
Vaccination campaigns require medically trained staff to ensure
that the dose is correctly injected and shows no obvious signs of
degradation. The need to reconstitute vials of some vaccines, such
as measles, yellow fever and BCG, in the field is also a serious
concern. Upon rehydration these vaccines become unstable again and
cannot be stored. They must be injected promptly after
reconstitution, which is often not possible in mass vaccination
campaigns. Reconstitution must be done precisely to ensure correct
dosage and it also introduces a potential source of contamination
which has led to clinical disasters.
It is often necessary to give more than one vaccine at a session
and if multivalent vaccines are not available due to the chemical
incompatibility of some of the components this may require 2 or
more injections. The WHO has highlighted these problems by actively
encouraging research into the next generation of stable multivalent
vaccines which are presented in single injections and have no need
for refrigeration (J. Lloyd. Technologies for vaccine delivery in
the 21st century. World Health Organization Geneva (2000) in
collaboration with Department Of Vaccines And Biologicals UNICEF.,
Lloyd J. and Aguado M. T. Pre-Filled monadose Injection Devices: A
safety standard for new vaccines, or a revolution in the delivery
of immunizations? WHO publication May (1998). Aguado M T., Jodar
L., Lloyd J., Lambert P. H. General Policy issues: injectable solid
vaccines: a role in future immunization?" WHO publication No
A59781).
INVENTION SUMMARY
To address the problems described above this invention proposes a
conventional pharmaceutical syringe comprising a pharmaceutical
material stabilised in a soluble dry glass coating the surfaces of
the voids in a compressible porous matrix which is located within
the barrel of the syringe between the plunger and the needle
fitting.
Upon drawing the water into the syringe the soluble glass rapidly
dissolves to release the pharmaceutical material into the water for
injection. Compression of the porous matrix at the end of the
injection stroke ensures delivery of the complete dose of
vaccine.
Accordingly, the syringe of the present invention is suitable for
the administration of a liquid-carried pharmaceutical to a patient.
The syringe contains a pharmaceutical stabilized in a glass that is
soluble in a carrier liquid (e.g. water, saline) and that is in a
compressible porous matrix located in the barrel of the syringe, so
that the glass dissolves in the carrier liquid thereby releasing
the pharmaceutical into the carrier liquid for administration to
the patient.
A wide range of bioactive molecules may be stabilized by drying in
soluble glasses, particularly sugar glasses (see e.g., U.S. Pat.
No. 4,891,319, GB2187191, U.S. Pat. No. 5,955,448). These dry,
stabilized actives are unaffected by high or freezing temperatures
The mechanism underlying the remarkable stabilization of molecules
by certain sugars is the ability of drying solutions to undergo
glass-transformation rather than crystallisation. The disaccharide
trehalose readily forms stable glasses (Green J L. & Angel C A.
Phase relations and vitrification in saccharide water solutions and
the trehalose anomaly J Phys. Chem. 93 2880-2882 (1989)) and has
excellent stabilising properties.
One of the advantages of the present invention is that the
compressible porous matrix having the pharmaceutical-containing
glass in it can be dried outside the syringe and then inserted it
into the syringe during the manufacturing step in a form that can
easily and cheaply be manufactured and stored at ambient
temperature without deterioration, and can be used immediately
without any set up. The drying can be achieved by air drying, which
is a convenient and low cost way of drying the glass that contains
the pharmaceutical.
The provision of stable, ready-to-inject dose formulations that are
relatively inexpensive and packed in the syringe itself greatly
reduces costs since the additional storage and delivery costs for
other equipment are saved. This is a particular advantage with
multiple component formulations containing more than one active
ingredient, such as multivalent vaccines. Difficulties with
chemical incompatibility of multiple components are reduced since
they are stored in a dry, stable form. Further, the need for
providing multiple phials containing the various active ingredients
is avoided.
The invention is further defined in the annexed statements of
invention and in the claims.
In a first aspect, the invention provides a syringe comprising a
pharmaceutical in a soluble glass, wherein the soluble glass is in
a compressible porous matrix. In a second aspect, the invention
provides a compressible porous matrix insert comprising a
pharmaceutical in a soluble glass, which insert is suitable for
insertion into the barrel of a syringe.
In relation to the first aspect, the invention provides a
pharmaceutical syringe, comprising a syringe barrel, and having a
compressible porous matrix in the syringe barrel, wherein the
compressible porous matrix has in it a pharmaceutical in a soluble
glass.
In relation to the second aspect, the invention provides a
compressible porous matrix insert, which is a body of a
compressible porous matrix having in it a pharmaceutical in a
soluble glass, which insert is suitable for inserting into the
barrel of a syringe for delivery of the pharmaceutical to a
subject.
Preferred or optional features of the invention will now be set
out. These may be applied singly or in any combination with any
aspect or development of the invention described herein, unless the
context demands otherwise.
The term syringe refers to a pharmaceutical syringe, which is a
syringe suitable for delivery of a pharmaceutical to a subject,
particularly parenteral delivery of a pharmaceutical to a subject
(a subject may also be referred to herein as a patient). The term
syringe used herein encompasses any pharmaceutical injection
device, for example a device used for mass inoculations. A syringe
typically comprises a barrel, which is a compartment for holding or
receiving a liquid for injection, and a plunger for actuating
discharging of the liquid from the barrel for delivery of the
liquid to a subject. The plunger may be fitted into one end of the
barrel, while the other end of the barrel has an outlet connected
to, or connectable to, a needle (e.g. a hypodermic needle) or a
tubing or further medical apparatus. A syringe plunger typically
has a sealing member at one end, which fits tightly into the
syringe barrel to form a water-tight seal. The sealing member is
also referred to herein as a seal. In use, depression of the
plunger into the barrel drives fluid (air and/or liquid) from the
barrel, out of the outlet at the needle end of the syringe, whereas
outward drawing of the plunger draws fluid into the barrel, in
through the needle end of the syringe. The drawing of fluid in to a
syringe may be referred to as aspiration. The driving of fluid out
of the syringe may be referred to as expelling or discharging or,
in the context of delivery of fluid to a patient, injecting.
Before the syringe of the present invention is used for the
delivery of a pharmaceutical to a subject, it is in a stored state.
The syringe in its stored state may have the plunger at least
partially in the barrel, or the plunger may be outside the barrel.
The plunger may be packaged separately from the barrel. In its
stored state the needle end of the syringe may be connected or
attached to a needle, or the needle may be supplied separately in
which case there is no needle connected or attached to the needle
end of the syringe. The syringe in its stored state may contain the
compressible porous matrix inside the barrel and/or the matrix may
be attached to the seal of the plunger. The syringe in its stored
state is typically stored in air and has air in the barrel. In its
stored state there is no carrier liquid in the syringe barrel. The
syringe may be provided in its stored state in a sterile and/or
vacuum packed packaging.
Porosity is the fraction of voids in a material. If the porosity of
a material is .PHI., then its density, .rho., is related to .PHI.
by .PHI.=(.rho..sub.0-.rho.)/.rho..sub.0 where .rho..sub.0 is the
pore-free density. Porosity can be expressed has a value between
0-1 or as a percentage between 0-100% where in the percentage
indicates the void fraction in the material. Porous matrices
suitable for use in the present invention may have porosities of up
to about 70%, up to about 80%, up to about 85%, up to about 90%, up
to about 95% or up to about 98%. Porous matrices suitable for use
in the present invention may have porosities of at least about 50%,
at least about 60%, at least about 70%, at least about 80%, at
least about 90% or at least about 95%. Porous matrices suitable for
use in the invention may have porosities of about 40-95%, about
50-95%, about 60-95%, about 70-95% or about 80-95%.
The porous matrices of the present invention preferably have a pore
size of between about 1 micron and about 2 mm, between about 10
micron and about 1 mm, or between about 10 micron and about 100
micron. The pore size refers to the mean pore diameter
The specific surface area of a porous matrix such as a foam is the
amount of surface area within a given volume or mass of foam. The
porous matrices for use in the present invention provide a large
surface area on which a solution of a glass-forming material may be
dried to provide a matrix with a glass in it. The porous matrices
of the invention preferably have a high specific surface area. The
porous matrices of the invention preferably have a specific surface
area of about 0.1-100 m.sup.2/g, about 1-100 m.sup.2/g, about 5-100
m.sup.2/g, about 10-100 m.sup.2/g, about 0.1-20 m.sup.2/g, about
1-20 m.sup.2/g, about 5-20 m.sup.2/g, about 10-20 m.sup.2/g, about
10-50 m.sup.2/g, about 10-500 m.sup.2/g, about 50-500 m.sup.2/g, at
least about 0.1 m.sup.2/g, at least about 1 m.sup.2/g, at least
about 10 m.sup.2/g, or about 10 m.sup.2/g or about 20
m.sup.2/g.
A compressible material accepts reduction in volume by applied
pressure to form a compact. A compressible material or product may
also be termed a compliant material or product. Compressibility in
the context of the present invention can be measured and/or
expressed as the ratio of the original non-compressed volume to the
volume of the compressed compact. A compressible matrix for use in
the present invention may have compressibility of about 5:1 or
more, meaning that its volume in its non-compressed state is about
five times or more greater than its volume in its compressed state,
A compressible matrix for use in the present invention may have a
compressibility of about 2:1 or more, about 3:1 or more, about 4:1
or more, about 5:1 or more, about 10:1 or more, about 20:1 or more,
or about 50:1 or more.
A compressible porous matrix may be a solid foam body, which is a
body comprising pockets or cells of gas in a solid. The foam is
preferably open cell foam, i.e. a foam in which some, or most of,
the gas pockets or cells connect with each other and to the outside
of the foam body. Pockets or cells of a porous matrix may also be
referred to as voids. Preferred foams are cellulose foams, melamine
foams and hydrophilic reticulated polyether foams. The porous
matrix may be formed from cellulose, polyethylene, polypropylene,
polyester, polyether polyurethane, polyurethane, polyvinyl acetate,
melamine formaldehyde resin or natural sponge.
The compressible porous matrix is preferably insoluble. That is,
the compressible porous matrix is insoluble in a carrier liquid
(e.g. water, saline), specifically, it is insoluble in the carrier
liquid that is to be used to deliver the pharmaceutical to the
subject. Preferably the compressible porous matrix is insoluble in
water.
A compressible porous matrix may be in the form of a block, a
cylinder, or a prism, optionally an elongate block, cylinder or
prism, which may have a circular or a non-circular (e.g.
rectangular) cross section. A matrix in the form of an elongate
block may be inserted, or contained in, a syringe barrel such that
the elongate block is lengthways along the longitudinal axis of the
syringe barrel. A compressible porous matrix may also be referred
to as a compressible porous supporting structure.
A glass is a non-crystalline solid. In particular, a glass is a
hard, brittle non-crystalline solid. Glasses are amorphous solids,
meaning that their structure lacks the regularity of crystalline
solids. Glasses may be defined as those noncrystalline solids which
exhibit a transition in behaviour (the glass transition) with
temperature. The term "glass" herein refers to any glassy material
or glassy substance, that is, any non-crystalline or amorphous
solid. In particular, the term glass herein relates to organic
glass, and refers to any solid formed from an organic glass-forming
material. A glass suitable for use in the present invention is a
soluble glass.
Glass-forming materials include amino acids, sugars, sugar
alcohols, carbohydrates, carbohydrate derivatives and polyols
(including carbohydrate and non-carbohydrate polyols) as described
herein. The glass-forming material may be any non-reactive
glass-forming sugar such as trehalose, raffinose or sucrose or
mixtures of sugars or any other carbohydrate glass-former.
Glass-forming materials are also referred to herein as stabilisers,
stabilising excipients, or preservatives, because a pharmaceutical
may be stored in the glass formed from the glass forming material
without substantial losses in activity by denaturation, aggregation
or other mechanisms.
A glass may be produced by preparing a solution of a glass-forming
material in a solvent, which solution may be referred to as a
preservative solution or a stabiliser solution. For example a
solution comprising about 5-50% w/v, about 10-30% w/v, or about
10-50% w/v glass-forming material, or a solution comprising about
5%, about 7.5%, about 10%, about 15%, about 20%, about 25%, about
30%, about 35%, about 40%, about 45% or about 50% w/v glass-forming
material. The glass-forming material may be trehalose. The glass
for use in the present invention is prepared by drying a solution
of glass-forming material, for example by air drying. The
glass-forming material in the glass-forming solution vitrifies upon
drying. In particular, the glass of the present invention may be
prepared by preparing a solution of 10-30% w/v trehalose and drying
the solution, preferably by air drying. In the preparation of
glasses for use in embodiments of the invention, a pharmaceutical
is also included in the glass-forming solution. Upon drying of the
glass-forming solution, the pharmaceutical is stabilised in the
glass. Such a glass may be referred to as a
pharmaceutical-containing glass.
A compressible porous matrix may have in it a glass comprising a
pharmaceutical. A porous matrix provides a large surface area on
which a glass-forming solution can be dried. The surface of the
matrix comprises the external surfaces of the matrix and the
internal surfaces which are formed by the pore-forming pockets,
cells, or voids or the matrix. Upon drying, the glass-forming
solution forms a glass in the porous matrix; in this context, a
glass in the porous matrix is a glass on at least some of the
internal surfaces of the matrix, i.e. the surfaces formed by the
pore-forming pockets, cells, or voids of the matrix. The internal
surfaces of the matrix are thus coated with glass. The matrix may
be referred to as coated with glass, or impregnated with glass.
The pharmaceutical in the glass is preferably stabilised in the
glass. Such a pharmaceutical may be termed herein a glass
stabilised pharmaceutical, a stabilised pharmaceutical, or a stable
pharmaceutical in a glass. The term stable or stabilised refers to
a substance, such as a pharmaceutical, which essentially retains
its physical and chemical stability and integrity upon storage. In
particular a stable or stabilised substance is a pharmaceutical
(such as a therapeutic protein or a vaccine) that retains its
activity, for example its biological or therapeutic activity, upon
storage. Various analytical techniques for measuring stability of
proteins are known and are reviewed in Jones, A. Adv. Drug Delivery
Rev. 10:29-90 (1993). Stability and/or activity can be measured
following storage at a selected temperature for a selected time
period. Biological or therapeutic activity may be measured for
example as enzymatic activity, binding activity (e.g. binding of an
antibody to its antigen) or ability to elicit a specific result or
response in vitro or in vivo.
The stable or stabilised pharmaceutical of the invention may be one
which retains at least about 30%, at least about 40%, at least
about 50%, at least about 60%, at least about 70%, at least about
80%, at least about 90%, at least about 95%, at least about 98% or
at least about 99% activity following storage for a period of up to
1, 2, 3, 4, 5, 6, or 7 days or up to 2, 4, 8, or 12 weeks, or up to
1, 2, 3, 4, 6, 8, 12, 24 or 36 months at a temperature of between
10-60.degree. C., 10-50.degree. C., 10-40.degree. C., 20-50.degree.
C., 20.40.degree. C., or at about 18.degree. C., 20.degree. C.,
25.degree. C., 37.degree. C., 45.degree. C., 50.degree. C.,
60.degree. C., or 70.degree. C. For example, a stable or stabilised
pharmaceutical the invention may be one which retains at least
about 80% activity following storage for 2, 4, 8 or 12 weeks at
37.degree. C., or may be one which retains at least about 80%
activity following storage for about 2, 4, 8 or 12 weeks at
45.degree. C. Percentage activity refers to the activity of the
pharmaceutical after storage as a percentage of the activity of the
same pharmaceutical in fresh (non-stored) form.
The term "soluble" refers to a substance that is capable of being
dissolved in or as if in a fluid. The term soluble herein may refer
to a substance, such as a glass, that is soluble in a solvent such
as water and/or an aqueous solvent such as physiological saline. In
the context of the present invention such a solvent may be termed a
carrier liquid. The term soluble may refer to a substance, such as
a glass, that is soluble in oil and/or an organic solvent. In the
context of the present invention a soluble glass is preferably
soluble in water.
Conversely the term "insoluble" refers to a substance that is not
capable of being dissolved in a fluid. The term insoluble herein
may refer to a compressible porous matrix that is insoluble in a
solvent such as water and/or an aqueous solvent such as
physiological saline. In the context of the present invention such
a solvent may be termed a carrier liquid. The term insoluble may
refer to a compressible porous matrix that is insoluble in oil
and/or an organic solvent. In the context of the present invention
a compressible porous matrix is preferably insoluble in water.
Preferably, a soluble glass is a dry soluble glass. The term "dry"
refers to a glass having a residual moisture content of about
0.1-10% w/w, 0.1-5% w/w, about 0.1-2.5% w/w, about 0.1-1% w/w,
about 0.05-1% w/w, about 0.1% w/w, about 0.5% w/w, about 1% w/w,
about 2.5% w/w, about 5% w/w, or about 10% w/w.
The term "pharmaceutical" refers to any pharmaceutical material,
pharmaceutical agent, or pharmaceutical product, including
therapeutic agents, drugs, and prophylactic agents such as
vaccines. The pharmaceutical may be any bioactive substance.
Pharmaceuticals include vaccines, anti-inflammatory drugs,
analgesics, antiarthritic drugs, antispasmodics, antidepressants,
antipsychotics, tranquillisers, antianxiety drugs, narcotic
antagonists, antiparkinsonism agents, cholinergic agonists,
chemotherapeutic drugs, immunosuppressive agents, antiviral agents,
antimicrobial agents, appetite suppressants, anticholinergics,
antiemetics, antihistaminics, antimigraine agents, coronary,
cerebral or peripheral vasodilators, hormonal agents,
contraceptives, antithrombotic agents, diuretics, antihypertensive
agents, cardiovascular drugs, opioids, and the like.
Pharmaceuticals may be any type of substance, Such substances
include, but are not limited to, subcellular compositions, cells,
bacteria, viruses and molecules including, but not limited to,
lipids, organics, proteins and peptides (synthetic and natural),
peptide mimetics, hormones (peptide, steroid and corticosteroid), D
and L amino acid polymers, oligosaccharides, polysaccharides,
nucleotides, oligonucleotides and nucleic acids, including DNA and
RNA, protein nucleic acid hybrids, small molecules and
physiologically active analogues thereof. Further, the modifiers
may be derived from natural sources or made by recombinant or
synthetic means and include analogues, agonists and homologs.
Pharmaceuticals may be substances which are prophylactically
active. In particular, such substances include immunogens such as
vaccines. Suitable vaccines include, but are not limited to, live
and attenuated viruses, nucleotide vectors encoding antigens, live
and attenuated bacteria, antigens, antigens plus adjuvants and
haptens coupled to carriers. Particularly preferred are vaccines
effective against diphtheria, tetanus, pertussis, botulinum,
cholera, Dengue, Hepatitis A, B, C and E, Haemophilus influenza b,
herpes virus, Helicobacterium pylori, influenza, Japanese
encephalitis, meningococci A, B and C, measles, mumps, papilloma
virus, pneumococci, polo, rubella, rotavirus, respiratory syncytial
virus, Shigella, tuberculosis, yellow fever and combinations
thereof. The antigenic component of vaccines may also be produced
by molecular biology techniques to produce recombinant peptides or
fusion proteins containing one or more portions of a protein
derived from a pathogen. For instance, fusion proteins containing
an antigen and the B subunit of cholera toxin have been shown to
induce an immune response to the antigen. Sanchez at al. (1989)
Proc. Natl A cad Sci. USA 86:481-0.485. Vaccines are particularly
suitable for incorporation into the single-dosage composition. They
are stable indefinitely under ambient conditions and can be
redissolved in sterile diluent immediately before inoculation.
Preferably, the immunogenic composition contains an amount of an
adjuvant sufficient to enhance the immune response to the
immunogen. Suitable adjuvants include, but are not limited to,
aluminium salts, calcium phosphate, squalene mixtures (SAF-1),
muramyl peptide, saponin derivatives, mycobacterium cell wall
preparations, monophosphoryllipid A, mycolic acid derivatives,
non-ionic block copolymer surfactants, Quil A, cholera toxin B
subunit, polyphosphazene and derivatives, and immunostimulating
complexes (ISCOMs) such as those described by Takahashi at al.
(1990) Nature 344:873-875. For veterinary use and for production of
antibodies in animals, antigenic components of Freund's adjuvant
can be used. As with all immunogenic compositions, the
immunologically effective amounts of the immunogens must be
determined empirically. Factors to be considered include the
immunogenicity, whether or not the immunogen will be complexed with
or covalently attached to an adjuvant or carrier protein or other
carrier, route of administration and the number of immunising
dosages to be administered. Such factors are known in the vaccine
art and it is well within the skill of immunologists to make such
determinations without undue experimentation. Multiple
pharmaceuticals can be included in the syringe or insert of the
present invention. Thus, the syringe or insert may contain two or
more different vaccines, for example 2, 3, 4 or 5 different
vaccines.
The compressible porous matrix insert of the invention is a body of
compressible porous matrix having in it a glass which contains a
pharmaceutical, which is suitable for insertion into the barrel of
a syringe. The syringe of the present invention has such a
compressible porous matrix pre-inserted in its barrel. The
compressible porous matrix may be in the form of a block, a
cylinder, or a prism, optionally an elongate block, cylinder or
prism, which may have a circular or a non-circular (e.g.
rectangular) cross section.
The compressible porous matrix may comprise a coloured substance.
The coloured substance may be an inert, non-toxic, injectable
substance which is present on the matrix in addition to the
pharmaceutical. Alternatively the pharmaceutical itself may be a
coloured substance. The coloured substance may be present on the
external surfaces of the matrix, or additionally or alternatively
on the internal surfaces of the matrix. The coloured substance
gives a colour to the matrix when the syringe barrel contains a
carrier liquid, which colour is reduced following depression of the
plunger in the syringe barrel to discharge the carrier liquid from
the syringe. During use of the syringe, when the carrier liquid
comprising the pharmaceutical is forced out of the outlet at the
needle end of the syringe barrel, at least some of the coloured
substance flows away from the matrix, thereby reducing the colour
of the matrix. The reduction in colour of the matrix is thus
associated with successful delivery of the pharmaceutical. The user
of a syringe containing the matrix is able to determine whether the
pharmaceutical has been delivered to the subject.
The present invention also provides methods for producing the
syringes and inserts of the invention, as well as methods of using
and uses of the syringes and inserts in the delivery of a
pharmaceutical to a subject.
The present invention provides a method of producing a
pharmaceutical syringe or a compressible porous matrix insert. The
method comprises contacting a compressible porous matrix with a
solution of a glass-forming material containing a pharmaceutical.
The solution of glass-forming material containing the
pharmaceutical may enter the cells of the matrix by capillary
action, and thereby coat the internal surfaces of the matrix (the
surfaces formed by the cells). Contacting the matrix with the
glass-forming solution may comprise dipping the matrix partially or
completely into the solution, or spraying the matrix with the
glass-forming solution. The matrix is then dried, preferably air
dried, such that the glass-forming solution in the matrix dries to
form a glass which comprises the pharmaceutical. The method may
further comprise treating the matrix with a blocking agent before
contacting it with the glass forming solution. Alternatively or
additionally, the method may further comprise treating the matrix
with a surfactant.
The present invention also provides a method of pre-loading a
syringe with a pharmaceutical, comprising inserting the
compressible porous matrix insert of the invention into the barrel
of a syringe. Any conventional syringe may be used, and thereby
pre-loaded with pharmaceutical. The amount of pharmaceutical
present in the glass on the compressible porous matrix insert may
correspond to a fixed or predetermined dose of that
pharmaceutical.
The invention also provides a method of preparing a pharmaceutical
for administration or delivery (e.g. injection) to a subject. In
this method the compressible porous matrix insert of the invention
is inserted into the barrel of a syringe, as described above, and
then a carrier liquid is forced through the compressible porous
matrix so that the pharmaceutical becomes dissolved or dispersed in
the carrier liquid prior to delivery to the patient. In this
method, after insertion of the insert into the barrel of the
syringe, a carrier liquid (e.g. water, saline) is drawn into the
syringe. The carrier liquid may then enter the matrix by capillary
action, causing the glass on the matrix to dissolve. The
pharmaceutical thus becomes dissolved, suspended, or dispersed in
the carrier liquid. When the carrier liquid is then forced out of
the syringe by depressing the plunger the matrix is compressed,
thereby forcing the carrier liquid out of the matrix, such that the
pharmaceutical in which it is dissolved or suspended is forced out
of the syringe.
The invention also provides a method of using a syringe or insert
of the invention for delivering or administering a pharmaceutical
to a subject (i.e. a patient). The method may comprise the method
of preparing a pharmaceutical for administration or delivery to a
subject as described above, and then delivering the pharmaceutical
to the patient by the normal injection process of depressing the
plunger of the syringe which compresses the porous matrix to expel
the pharmaceutical into the injected liquid and thereby into the
patient.
The invention also provides a kit of parts, comprising a
compressible porous matrix insert of the invention, a syringe
barrel, and a syringe plunger. The insert is suitable for inserting
into the syringe barrel. The kit may further comprise a carrier
liquid, which carrier liquid is an aqueous solvent or an organic
solvent. In use the carrier liquid acts as a solvent for dissolving
the glass, such that the pharmaceutical in the glass becomes
dissolved, suspended or dispersed in the carrier liquid. The kit
may further comprise a needle for connecting to the needle end of
the syringe barrel.
The carrier liquid is a liquid for carrying the pharmaceutical for
delivery to a subject. The carrier liquid acts is a solvent for the
glass in which the pharmaceutical is contained. The carrier liquid
may be an aqueous solvent (an aqueous liquid) or an organic solvent
(an organic liquid). Preferred carrier liquids are water
(specifically sterile water for injection, or bacteriostatic water
for injection) and saline (specifically physiological saline).
The present invention also provides a pharmaceutical syringe or
compressible porous matrix insert as described herein, wherein the
insert is fixed to the seal of a syringe plunger. The insert may be
fixed to the seal by any means, for example by a glue or a
fastening. The syringe plunger bearing the insert is suitable for
use with a syringe barrel to provide an operable syringe.
An example of the invention, and experimental results underlying
the present invention, will now be described by referring to the
accompanying drawings:
FIG. 1 Shows the improved syringe as supplied with the dry
pharmaceutical in a porous matrix in the barrel
FIG. 2 is a transverse cross section showing the rehydrated porous
matrix and its relationship with the walls of the barrel
FIG. 3 shows the filling of the syringe with sterile water or
saline and rehydration of the vaccine for injection
FIG. 4 shows the injection of the solubilised pharmaceutical and
it's expulsion from the porous matrix by compression
FIG. 5 shows the results of experimental example 3.
FIGS. 6A and 6B show the results of experimental example 5.
FIGS. 7A and 7B show the results of experimental example 6.
DETAILED DESCRIPTION OF THE FIGURES
FIG. 1a: Axial cross-section through a syringe containing the
pre-loaded porous matrix. The syringe is illustrated in the
configuration as it is in storage. The syringe barrel 1 has an open
end 2 through which is inserted a plunger 3 with an attached
sealing member 4 making a water-tight seal with the interior
syringe barrel wall 18 of the barrel which houses the dried porous
matrix 5 containing the glass-stabilised product. In certain
embodiments, the porous matrix 5 may be fixed to the seal by, for
example, a glue or a fastening 17. The porous matrix is located
inside the barrel between the sealing member and the needle end
with its attached hypodermic needle 6. The dashed line 7 is the
location of the transverse cross section in FIG. 1b
FIG. 1b: Transverse cross section of one configuration of the
porous matrix, after it has been rehydrated to its original
dimensions, showing the circular barrel of the syringe 8 containing
a porous sponge of rectangular cross section 9 which makes contact
with the barrel inner surface only at the corners leaving a
circle-segment shaped space on each of the sides which allows the
free passage of any trapped air during purging of the syringe. The
axial cross sections of FIGS. 1a, 2, 3 and 4 are made at the
location of the dashed line 10.
FIG. 2: Axial cross-section through a syringe containing the porous
matrix 9 rehydrated after the needle 6 is inserted into a vial of
sterile water for injection 11, by withdrawal of the plunger 12
which rehydrates the porous matrix 9 with the aspirated water 13
and dissolves the glass stabilised vaccine.
FIG. 3: Axial cross-section through a syringe containing the porous
matrix in the inverted position, after the air has been expelled
through the needle, ready for injection.
FIG. 4: Axial cross-section through a syringe containing the porous
matrix at the point of injection when the needle is inserted into
the subcutaneous, intramuscular or intravenous location 14. By
depressing the plunger completely to the needle end, the porous
matrix is compressed 15 to expel the full dose into the injection
site 16.
FIG. 5: Aluminium hydroxide was dried in 7.5% w/v, 15% w/v and 30%
w/v trehalose buffer and recovered up to 30 days after storage at
55.degree. C. Recovery was measured by column sedimentation. At 15%
w/v trehalose concentration and above this adjuvant is recovered
fully intact.
FIG. 6A: Recovered dried HepB shows long term stability after
storage at various temperatures for six months. The majority of the
vaccine is recovered in intact form except at 70.degree. C. Control
is fresh (non-stored) vaccine.
FIG. 6B: Antibody response of groups of 5 mice given three
different doses of Hepatitis B vaccine either fresh or stabilised
in trehalose with storage at 55.degree. C. for two months. All
responses are equivalent to fresh vaccine within the variability of
the assay.
FIG. 7A: Recovery of adjuvanted tetanus vaccine after drying in
trehalose buffer and storage for more than eight months. While
non-stabilised vaccine lost some activity on drying and all
activity on storage, stabilised vaccine was recovered intact.
Recovery of intact vaccine was determined by immunoassay.
FIG. 7B: Antibody levels measured in three groups of 10 mice at 4,
8 or 12 weeks after injection with either fresh (non-stored)
vaccine or two different dried formulations of trehalose buffer
(treh 1 and treh 2) stored at 37.degree. prior to injection The
immune response of the mice to both dried preparations was
equivalent to fresh vaccine within the variability of the
assay.
Obviously, variations can be made to the described format without
departing from the substance of the invention. For example, the
product could be a vaccine drug or any biological material that
would normally be subject to degradation if stored in liquid
solution or suspension. This includes products such as hormones,
protein and viral vaccines and genetic material. The glass forming
material could be any non reactive glass-forming sugars such as
trehalose, raffinose or sucrose or mixtures of sugars or any other
carbohydrate glass-former; also glass-forming amino acids such as
monosodium glutamate (MSG), monosodium aspartate (MSA) or a MSG/MSA
mixture or other soluble stabilising glasses or mixtures of the
above could be used; and the syringe could be either a standard
syringe or an auto-disable syringe or other liquid delivery device
or a device for mass inoculations. In an alternative embodiment,
the carrier liquid could be an emulsion of the oil-in-water or
water-in-oii type and as such the active product could become
associated with the aqueous phase of the emulsion as the aqueous
phase dissolves the glass. In a further alternative, an oil solvent
could be used in conjunction with a hydrophobic pharmaceutical
stabilised in an oil soluble glass.
DETAILED DESCRIPTION
The present invention is an improvement on the syringes typically
used to give parenteral injections of pharmaceutical agents. It
incorporates the pharmaceutical material stabilised by drying it in
a solution of a stabilising excipient, for example trehalose, to
form a glass in a three dimensional and compressible porous matrix
which is then located within the barrel of a conventional plastic
syringe between the plunger and the needle fitting. This syringe
can then be stored for prolonged periods at ambient temperatures
and is ready for instant use. Upon drawing up the water for
injection, capillary action draws the solvent liquid into the
porous matrix and the soluble glass therein rapidly dissolves to
release the pharmaceutical into the liquid for injection. A
significant advantage of the present invention is that it uses no
additional housings and is designed to be made with minimal change
to existing manufacturing processes. In use it also requires no
changes from standard injection technique and requires no training.
It is therefore of minimal cost.
In a preferred realisation of the present invention the
pharmaceutical material is dried in a compressible porous matrix in
a wide range of possible sizes and is then introduced into the
barrel of an appropriately sized syringe, which syringe typically
has an internal volume larger than the matrix. Thus even a large
volume of porous matrix can be accommodated in the syringe and a
consequently large volume of active product dried therein.
For example a compressible porous matrix in the form of a
rectangular block measuring 6 mm.times.6 mm.times.10 mm in its
non-compressed state, and having a glass comprising a
pharmaceutical in it, may be introduced into the barrel of a 2 ml
syringe (a syringe having a maximum dispensing volume of 2 ml). In
this example the compressible porous matrix in its non-compressed
state occupies 18% of the volume of the syringe barrel (the nominal
internal volume of the syringe). The compressible porous matrix in
its non-compressed state may occupy at least about 10%, at least
about 20%, at least about 30%, at least about 40%, at least about
50%, at least about 60%, at least about 70%, at least about 80%, at
least about 90%, about 10-90%, about 20-90%, about 30-90%, about
40-90%, about 50-90%, about 10%, about 20%, about 30%, about 40%,
about 50%, about 60%, about 70%, about 80% or about 90% of the
volume of the syringe barrel into which it is to be inserted for
use. Typical syringes for use in the present invention will have
volumes of between about 1-10 ml, and therefore typical
compressible porous matrix blocks for use in the present invention
may have volumes of between about 0.1-9 ml (100-9000 mm.sup.3)
depending on which size of syringe they are to be inserted into for
use. The volume of a syringe refers to the volume of the barrel of
the syringe, that is the internal volume of the cylindrical
compartment in the syringe which holds the liquid for injection
(so, for example, a "2 ml syringe" has a barrel volume of 2 ml),
The compressible porous matrix may be biased towards its
non-compressed (expanded) state, which means that during use
depression of the syringe plunger is needed in order to force the
porous matrix into its compressed form.
In addition to the standard disposable plastic syringes a variety
of other injectors maybe used. These include without restriction,
glass syringes, auto-disable syringes, retractable needle syringes
and other injection devices. Such devices may have a compartment
for holding a liquid for injection comprising a compressible porous
matrix insert of the invention. The compressible porous matrix of
the invention may be suitable for inserting into the liquid-holding
compartment of such a device. Thus the present invention provides a
method of storing and or transporting a pharmaceutical stabilized
in a glass that is soluble in a carrier liquid, wherein the
pharmaceutical is stored in a compressible porous supporting
structure in a passage for the flow of the said liquid so that the
agent can be administered by aspirating the carrier liquid into the
spaces or pores of the supporting structure and then causing the
liquid to be expelled through the passage and thence to the patient
as the porous supporting structure is compressed.
Many drugs and highly multivalent vaccines can easily be stabilised
in the syringe with a minimal requirement for prior concentration.
A normal injection procedure is used in which the practitioner
inserts the needle into a vial of sterile water or saline and
withdraws the required volume of liquid into the syringe and then
injects the active product into the patient. This is the procedure
currently used and is familiar to health care workers, thereby
reducing the need for additional training and the chances of error.
Indeed, because the appropriate dose is already in the syringe as
supplied, any error in the volume of liquid aspirated (providing it
is sufficient to dissolve the pharmaceutical) does not alter the
dose delivered to the patient
In another novel realisation of the present invention the porous
matrix containing the pharmaceutical product is easily compressed
after rehydration. The aspiration of the water starts the
dissolution of soluble glass containing the pharmaceutical as the
liquid permeates the porous matrix by capillarity. For injection,
the plunger of the syringe is depressed, preferably fully
depressed, causing the compression of the porous matrix thus
expelling the liquid contained therein, preferably all, or
essentially all of the liquid contained therein, and the full dose
of the pharmaceutical is delivered into the patient. The injection
process can also be made to activate the disabling step of an
auto-disable syringe rendering it incapable of reuse.
A compressible porous matrix comprising a pharmaceutical is a
compressible porous matrix insert, suitable for inserting into the
barrel of a syringe for use in delivery of the pharmaceutical. In
use, the compressible porous matrix is compressed by the action of
depressing the syringe plunger, that is, the action of urging the
syringe plunger towards the needle end of the syringe barrel. In
use, the syringe plunger draws a volume of solvent, or carrier
liquid, (e.g. sterile water, saline) into the barrel of the syringe
by the action of raising the plunger, that is the action of urging
the syringe plunger towards the open end of the syringe barrel
(away from the needle end of the syringe barrel). The solvent
rehydrates the porous matrix. The solvent is drawn into the porous
matrix and dissolves the glass in which the pharmaceutical is
comprised, such that the pharmaceutical becomes dissolved or
suspended in the carrier liquid. The plunger is then depressed to
deliver the pharmaceutical to a subject. This depression of the
plunger compresses the porous matrix into its compressed state.
The compressibility of the porous matrix is advantageous because
the action of compressing the porous matrix forces pharmaceutical
out of the porous matrix, where it would otherwise tend to be held
in the carrier liquid by the capillarity of the porous matrix. The
action of compressing the porous matrix forces the pharmaceutical
out of the syringe for delivery to a subject. Preferably in use the
action of depressing the syringe plunger is capable of forcing out
of the syringe (i.e. discharging or expelling from the syringe
barrel) at least about 60%, at least about 70%, at least about 80%,
at least about 90%, at least about 95%, at least about 98%, at
least about 99% or substantially 100% of the pharmaceutical, that
is the pharmaceutical that was in the glass.
We have found that some porous matrices although hydrophilic,
absorb water slowly. This problem can be overcome and water uptake
greatly accelerated by the addition of small quantities of an inert
biocompatible surfactant to the glass-forming solution prior to
loading the matrix with the pharmaceutical in the stabilising
solution and drying. When such a syringe eventually comes to be
used, the surfactant dried in the matrix facilitates the uptake of
solvent and the rapid rehydration of the glassified product. The
use of surfactant in the same way can even render certain
hydrophobic foams suitable as matrices for water-soluble products.
Examples of suitable surfactants include without limitation
polyoxyl castor oils, polysorbates and other injectable surfactants
approved by regulatory authorities.
In some cases however, the recovery of the product may be reduced
by physicochemical binding of the substance to the surfaces of the
porous matrix. This can be overcome by prior treatment of the
porous matrix with a blocking agent optionally followed by washing
to remove surplus blocking agent and re-drying. Examples of
blocking agents include, without limitation, proteins like caseins
or serum albumins, surfactants such as the polysorbate detergents
Tween 20 or Tween 80 or polymers such as polyvinyl pyrrolidone or
polyvinyl alcohols.
In manufacture of the present invention, the pharmaceutical product
is mixed, either dissolved or in suspension, with preservative
solution. It is absorbed by capillarity into the porous matrix and
then dried by any simple process such as air drying, vacuum drying,
freeze drying etc. Preferably it is dried outside the syringe.
Preferably, the preservative solution (glass-farming solution) is
dried by air drying to form a glass (i.e. a noncrystalline solid).
Air drying is convenient, inexpensive, and may be done at any
ambient temperature (e.g. room temperature), at about 15.degree. C.
or higher, about 20.degree. C. or higher, about 25.degree. C. or
higher, about 30.degree. C. or higher, at about 40.degree. C. or
higher, at about 50.degree. C. or higher, at about 60.degree. C. or
higher, at about 70.degree. C. or higher, at about 10.degree. C. to
about 70.degree. C., at about 10.degree. C. to about 60.degree. C.,
at about 10.degree. C. to about 50.degree. C., at about 20.degree.
C. to about 70.degree. C., at about 20.degree. C. to about
60.degree. C., at about 20.degree. C. to about 50.degree. C., at
about 20.degree. C. to about 40.degree. C., at about 15.degree. C.
to about 45.degree. C., at about 20.degree. C. to about 40.degree.
C. or at about 18.degree. C. to 25.degree. C. Air drying may be
done at atmospheric pressure (approximately 100 kPa). The
preservative solution may be dried by air drying overnight, or over
a period of about 1, 2, 4, 8, 16 or 24 hours or more. A low
relative humidity may be used during drying, for example of between
about 0-20% or 2-10%. Glass formation may optionally be facilitated
by using a solution purged of any less soluble solids by filtration
and/or by boiling. Drying a preservative solution on a porous
matrix outside the syringe is convenient and low cost, compared
with methods of drying a preservative solution while it is inside
the barrel of the syringe. This is at least partly because drying a
preservative solution on a porous matrix outside the barrel of the
syringe may be done by air drying, rather than vacuum drying or
freeze drying.
In the present invention a pharmaceutical is included in the
glass-forming solution before drying and is stabilised in the
resultant glass. Methods for stabilising products such as
pharmaceuticals (including biological therapeutics) are known and
are described for example in U.S. Pat. No. 4,892,319, GB2187191,
U.S. Pat. No. 5,955,448, WO96/40077 and WO2011/098837. In the
present invention, the glass containing the stabilised
pharmaceutical may form a layer on the surfaces of the voids or
cells in the compressible porous matrix. The relative thinness of
this layer means that the pharmaceutical-containing glass dries
very rapidly and thoroughly and then subsequently dissolves
relatively quickly upon contact with a solvent that may be drawn
into the barrel of a syringe for injection (e.g. sterile water or
saline).
Examples of preservatives include, without limitation, trehalose,
raffinose or sucrose and structural isomers thereof or mixtures of
these or any other carbohydrate glass former, glass-forming amino
acids such as monosodium glutamate (MSG), monosodium aspartate
(MSA) or a MSG/MSA mixture or other soluble stabilising glasses may
also be used. The manufacturing process requires minimal additional
equipment to that currently used. Because the volume of each of the
porous matrices used with any particular product at the same they
can be loaded with the correct dose of product by precise delivery
to each dry matrix insert when the dose is uniformly distributed by
capillary action.
Alternatively because the capillarity of each porous matrix insert
precisely made from the same batch is essentially the same, each
insert will naturally aspirate the same volume of drug from bulk
solution. For pharmaceuticals where the dose is not excessively
critical, this can provide a simple and inexpensive method for
dosing the syringes with standard doses of pharmaceutical. The
improvement is made by simply inserting the dried porous matrix
into a standard syringe, such as a disposable plastic one, so that
costs are little affected, making these improved stable products
competitively priced with existing ones.
The nature of the porous matrix insert used in the syringe is not
restricted and alternatives maybe obvious to those skilled in the
art. A porous, open-cell foam or sponge has been found to be ideal
but flexible woven or felted fabric on which the active product is
glass-dried and which is then folded or crumpled into the syringe
barrel can also work, in fact, any compressible porous matrix
whether made by foaming or by woven or felted fibres is suitable.
The porous matrix should be of high grade, sterilisable, suitable
for housing parenterally injectable substances and that it is not
particle or fibre-shedding nor contains toxic extractable
chemicals. The porous matrix should be insoluble. The matrix, which
is compressed against the aperture to the needle by the plunger,
should not obstruct the aperture. In practice, appropriate matrices
with good open cell structure are still fully porous when
compressed and do not suffer from this problem. For the usual water
soluble pharmaceuticals a preferred feature is that the porous
matrix be of a hydrophilic nature in order to readily absorb the
solution of pharmaceutical by capillarity and to redissolve it for
injection. Example materials in the manufacture of the porous
matrix include, without limitation, open cell foamed materials such
as cellulose or melamine foams; felted material such as polyester
fibre locked needlefelt or woven fabrics such as silk, cotton or
synthetic hydrophilic fabrics that are sufficiently soft to be
folded, crumpled or compressed for insertion into the syringe
barrel. Preferred matrices are cellulose foam, polyurethane foam
and melamine foam.
In a preferred embodiment of the invention, simple refinements of
the porous matrix render the syringe easier to use. After the
aspiration of the water there remains a volume of air in the
syringe that was present before aspiration and it must be removed
by venting before injection. It is also important to avoid forcing
the air through the porous matrix insert thereby displacing the
liquid when venting the air before injection. To preserve the
simplicity and familiarity of use, the air should be vented by the
usual manoeuvre, of expelling the air by holding the syringe
vertically with needle uppermost and driving the air out through
the needle by depressing the plunger until the syringe contains
liquid only. Preferably, therefore, the compressible porous matrix
is shaped and/or sized to provide a gap for passage of air through
or around the matrix when the matrix is inserted in the syringe
barrel, for allowing passage of air through the gap on venting of
the syringe.
The syringe of the invention may have a gap for the passage of air
during venting of the syringe, which gap is present between the
matrix and the inner wall of the syringe barrel. When the syringe
contains a carrier liquid and the needle end of the syringe is held
uppermost, the gap allows air bubbles to move to the outlet at the
needle end of the syringe and to be expelled from the syringe
before injection. Such a gap can be provided in a syringe barrel of
circular cross section by providing a compressible porous insert
which is a block, cylinder or prism having a non-circular cross
section, for example a cuboidal or rectangular block or a cylinder
having an oval cross section. Venting of the syringe can also be
facilitated by various modifications including making the porous
matrix insert non-circular, for example square, in cross section
and located inside the circular barrel without lateral compression.
For example, when the porous matrix insert is square in cross
section any air trapped between the porous matrix insert and the
plunger is easily vented around the insert via the circle-segment
shaped gaps between the flat sides of the insert and the circular
inner surface of the barrel. Capillary forces in the matrix ensure
the liquid remains in the insert during this venting. A similar
refinement can also be achieved by fabricating the porous matrix as
a cylindrical shape with an external diameter smaller than the
internal diameter of the barrel or as a hollow cylinder fitting
snugly in the barrel. Other formats of the porous matrix to achieve
easy air venting are obviously possible and are evident to the
skilled practitioner. In a further realisation the porous matrix
insert containing the stabilised pharmaceutical material is fixed
to the seal at the end of the syringe plunger so that entrained air
is naturally located above the insert during the venting manoeuvre.
The porous matrix insert may be fixed to the seal by, for example,
a glue or a fastening. The geometry of the insert may then vary
from a centrally located cylinder, a cylinder that occupies the
full diameter of the syringe barrel, or alternative shapes and
sizes that facilitate rapid release of the contained stabilised
pharmaceutical. The cross-sectional diameter, or cross-sectional
maximum width (width at the widest point of the transverse cross
section; transverse to the longitudinal axis of the syringe when
inserted), of the porous matrix insert may be smaller, around the
same as, or larger than the internal diameter of the syringe
barrel. If the cross-sectional diameter, or maximum width, of the
porous matrix insert is larger than the internal diameter of the
syringe barrel, then the insert may be inserted into the barrel
with lateral compression. A further refinement can be the addition
of an inert, non toxic, injectable, coloured substance to the
active product, thus altering the observed colour of the porous
matrix insert when it is absorbed and dried. The colour can be made
specific to the particular pharmaceutical thus identifying which
product is present in the syringe and ensuring the injection of the
correct one. After use, the colour flushes from the porous matrix
along with the active product thus uncovering the native colour of
the matrix. Completeness of colour change can demonstrate injection
of the full dose of active product. Also, the loss of colour in the
porous matrix shows that the syringe has been used and reduces the
possibility of accidental reuse. Suitable coloured substances
include fluorescein.
Of course the quantity of pharmaceutical material stored and
delivered in this method described herein can vary over a very wide
range by tailoring the size of the porous matrix insert to fit any
size of syringe. Since the porous matrix is chosen to have a very
high capacity to absorb water (of the order of 50 millilitres per
gram), there is needed little or no additional increase in the size
or the bulkiness of the syringe to accommodate the porous matrix
insert. Theoretically, there is no physical limit to the size of
the syringe or the contained insert.
The present invention is further illustrated by the following 7
Examples that are illustrative and are not intended to be limiting
in their scope.
EXAMPLES
In these studies of the glass-forming solutions used contained
dissolved trehalose at a concentration of 10-20% My or 10-30% w/v.
The solutions were either dried by air drying at about 50.degree.
C., or spray drying at about 45.degree. C.
Example 1
Materials Suitable as the Porous Matrix
A programme of selection for the properties of the optimal porous
matrix screened 36 foams, sponges and fibrous felts some of which
were rejected because they were non absorbent closed-cell foams or
of inappropriate pore sizes. Analysis of the remaining open cell
matrices identified as foamed materials possessing most of the
properties required, cellulose foam, melamine foam and hydrophilic
reticulated polyether foam. A comparison of these showed that
cellulose foam (FT-SPX Foam Techniques, Northants, NN8 6GR, UK) was
superior to the others in that it was very absorbent, easy to wash
clean and sterilise, free of plasticisers and other toxic
additives, dried rapidly and evenly and was inexpensive. Commercial
Melamine foam (FT-11 M Basotect, density 11 kg/m.sup.3, Foam
Techniques, Northants, NN8 6GR, UK) also hydrated instantly on
re-wetting without entrapped air bubbles and was soft and very
compressible on injection releasing nearly all of the absorbed
liquid.
Example 2
Testing Release of Model Product
A model system was used to examine the behaviour of a porous matrix
in the syringe. Rectangular blocks of cellulose foam measuring 6
mm.times.6 mm.times.10 mm were saturated with 10% w/v sugar glass
forming solution containing a red Carmoisine dye and placed in an
oven at 40.degree. C. It was fully dried within 2 hours with slight
but obvious shrinkage. It was loaded into a 2 ml plastic syringe.
0.8 ml of water was then aspirated into the syringe. The dry porous
matrix immediately filled with water by capillary action, regained
its previous volume when wet and the dye began to dissolve into the
water. The air bubble was readily expelled from the syringe in the
usual way. The liquid was then injected dropwise into a glass
vessel by depressing the plunger to fully compress the porous
matrix insert. All or nearly all of the dye appeared in the
receiving vessel. On withdrawing the plunger after injection the
porous matrix insert partially re-expanded to reveal that the
Carmoisine had been expelled so that the porous matrix had nearly
reverted to its native colour with only a pale residual pink
colour.
Example 3
Recovery of Particulate Aluminium Hydroxide Adjuvant
The possible entrapment of colloidal particles or aggregates within
the pores of the matrix was tested by using the approved vaccine
adjuvant Aluminium hydroxide. Recovery of this material is
essential for the use of vaccines in the syringe since a major
proportion of the vaccine antigens are physicochemically bound to
the adjuvant and would be lost if significant entrapment occurred.
This colloidal substance in aqueous suspension was mixed with
trehalose solution and dried Measurement of the quantity of
adjuvant loaded and the amount recovered indicated recovery of
about 90% of the adjuvant. The results of this experiment are shown
in FIG. 5. In embodiments of the invention, the colloidal substance
in aqueous suspension may be mixed with trehalose and dried in a
porous cellulose porous matrix block. The block could be inserted
into the barrel of a 2 ml syringe and 0.6 ml of water aspirated to
measure the recovery of aluminium hydroxide adjuvant. Air may be
expelled and the contents of the syringe injected into a vial.
Based on the results shown in FIG. 5, measurement of the quantity
of adjuvant loaded into the porous matrix would be expected to
indicate recovery of about 90% of the adjuvant.
Example 4
Recovery of Model Protein Pharmaceutical
Alkaline phosphatase enzyme was used as a model protein for
stability and recovery studies. It was loaded and dried in a porous
matrix. Some matrices were placed into stability studies. The
recovery of protein from the matrix was then measured.
Substantially all the protein as measured by enzymatic activity was
recovered even after storage at 37.degree. C. or 45.degree. C. for
three months. Variation of the numerical result is the result of
variability in the assay. These results indicate approximately 100%
recovery of active protein. The results of this experiment are
shown in Table 1, below. In embodiments of the invention a protein
of interest may be loaded and dried in a porous matrix block (e.g.
a cellulose porous matrix block). The block could then be placed in
a syringe. Some syringes could then be placed in stability studies
to measure recovery of protein from the matrix. Based on the
results shown in Table 1, below, substantially all the protein as
measured by enzymatic activity would be expected to be recovered
after storage at 45.degree. C. for three months.
TABLE-US-00001 TABLE 1 % Alkaline phosphatase recovered Experiment
Matrix stored at 37.degree. C. Matrix stored at 45.degree. C. 1
100.4 111.3 2 85.5 92.7 3 99.8 82.4
Example 5
Recovery of Adjuvanted Hepatitis B Vaccine
The adjuvanted vaccine Hepatitis B was dried in a trehalose buffer.
Some were set up for stability studies (results shown in FIG. 6A),
others used for recovery experiments and a third set were put into
stability studies and after a period were tested for their
immunogenicity in mice (results shown in FIG. 6B), The results
showed that immediate recovery, recovery after stability studies
and immunogenicity of this vaccine were all equivalent to fresh
vaccine.
Example 6
Recovery of Adjuvanted Tetanus Toxoid Vaccine
To confirm the generality of the findings adjuvanted tetanus toxoid
vaccine was dried as above on a porous matrix. Some were set up for
stability studies, others used for recovery experiments (results
shown in FIG. 7A) and a third set were put into stability study
conditions and after a period were tested for their immunogenicity
in mice by measuring serum antibodies (results shown in FIG. 7B).
The results showed that immediate recovery and, recovery after
stability studies and immunogenicity of this vaccine were all
equivalent to fresh vaccine.
Example 7
Potency of Recovered Stabilised Vaccine
To ensure that the protective clinical effect of vaccination is
retained when using this technology, syringes loaded with
stabilised tetanus vaccine as in example 6 are used to vaccinate
mice which are then challenged with a lethal dose of active tetanus
toxin. It is shown that the stabilised vaccine and syringe provide
the normal levels of protection by a result in which control mice
are killed, whereas mice immunised with either fresh vaccine or the
stabilised vaccine survive the challenge.
STATEMENTS OF INVENTION
The following numbered statements set out aspects of the invention
and form part of the description. 1. A pharmaceutical syringe
comprising a pharmaceutical material stabilised in a soluble dry
glass coating the surfaces of the voids in a compressible porous
matrix which is located within the barrel of the syringe between
the plunger and the needle fitting. 2. A pharmaceutical syringe
according to statement 1 characterised in that the porous matrix is
compressible. 3. A pharmaceutical syringe according to state en or
2 characterised in that the porous matrix is a sponge. 4. A
pharmaceutical syringe according to statement 1 or 2 characterised
in that the porous matrix is a fibrous body. 5. A pharmaceutical
syringe according to statement 2, 3, or 4 characterised in that the
porous body is formed from a natural material 6. A pharmaceutical
syringe according to statement 2, 3 and/or 4 characterised in that
the porous matrix is formed from a synthetic plastics material. 7.
A pharmaceutical syringe according to statement 5 characterised in
that the porous body is formed from a natural sponge. 8. A
pharmaceutical syringe according to statement 2, 3 and/or 4
characterised in that the porous matrix is formed from cellulose,
polyethylene, polypropylene, polyester, polyether polyurethane,
polyvinyl acetate or melamine formaldehyde resin. 9. A
pharmaceutical syringe according to statements 2, 3, 4, 5, 6, 7 or
8 characterised in that the porous matrix has a functional pore
size of between 1 micron and 2 mm. 10. A pharmaceutical syringe
according to statements 2, 3, 4, 5, 6, 7 or 8 characterised in that
the porous matrix has a functional pore size of between 10 microns
and 1 mm. 11. A pharmaceutical syringe according to statements 2,
3, 4, 5, 6, 7 or 8 characterised in that the porous matrix has a
functional pore size of between 10 microns and 100 microns. 12. A
pharmaceutical syringe according to statement 4 characterised in
that the glassy substances forms a coating on the surface of the
fibres or pores thus defining spaces allowing the liquid to pass
through. 13. A pharmaceutical syringe according to statement 1
characterised in that the carrier liquid is aqueous. 14. A
pharmaceutical syringe according to statement 1 characterised in
that the carrier liquid is an organic solvent. 15. A pharmaceutical
syringe according to any previous statement characterised in that
the porous matrix is treated with a blocking agent. 16. A
pharmaceutical syringe according to any previous statement
characterised in that the porous matrix is treated with a
surfactant. 17. A pharmaceutical syringe according to statement 1
characterised in that the porous matrix is hydrophilic for the
application of water soluble glassy substances and hydrophobic for
the application of oil soluble glassy substances. 18. A
pharmaceutical syringe according to any previous statement
characterised in that the glass is an amino acid glass, a sugar
glass, a hydrophobically modified sugar glass, a carbohydrate
glass, or mixtures thereof the syringe being for the administration
of a liquid-carried pharmaceutical to a patient characterised by an
active pharmaceutical material stabilized in a glassy material that
is soluble in the liquid and that forms a coating on supporting
means located in the passage so that the glassy material will
dissolve in the liquid thereby releasing the pharmaceutical into
the liquid. 19. A method of storing and or transporting a
biological agent stabilized in a glassy substance soluble in a
carrier liquid characterised in that the biological agent is stored
in a compressible porous supporting structure in a passage for the
flow of the said liquid so that, the agent can be administered by
aspirating the carrier liquid into the spaces or pores of the
supporting structure and then causing the liquid to be expelled
through the passage and thence to the patient as the porous
supporting structure is compressed. 20. A method of preparing a
pharmaceutical prior to administration to a patient in which a
carrier liquid is caused to flow along a passage containing an
active ingredient stabilised by a glassy substance so that the
agent becomes dissolved or dispersed in the liquid prior to
delivery to the patient. 21. A pharmaceutical syringe defining a
spongy or fibrous body and glassy material stabilising an active
ingredient deposited on the pores of the porous matrix or the
fibres of the fibrous body, the coated pores or fibres defining
spaces between them whereby a solvent can pass through the matrix
dissolving the glassy substance.
* * * * *